The present invention relates to a design cooperation system for items of design for use in design as viewed from a plurality of standpoints such as desired reliability, producibility and operatability and for determining product specifications. In particular, the present invention relates to a method and system for cooperated design for obtaining optimum design values as viewed from overall standpoints by evaluating a plurality of design items as viewed from the overall standpoints and supporting collaboration work among sections designing the design items.
So far, a number of analysis techniques and systems for evaluating and determining design specifications of a product have been announced.
A representative example of such analysis techniques and systems is an analysis and evaluation technique and system for performing flow and cooling analyses in the design of a molding die. This analysis and evaluation technique and system are discussed on pages 16 to 19 of Chapter 2, Edition No. 11, Volume 2 of "Die Technologies" published by Nikkan Kogyo Newspaper Company on Oct. 20, 1987. According to this representative example of the conventional technologies, in a typical conventional technology, in order to design a die, it is necessary to carry out, among other analyses, flow, thermal-stress and structure analyses one after another in accordance with the molding process and then to verify design specifications individually by utilizing results of the analyses. In this case, the example is a tool for building a product. Accordingly, specifications of the product naturally have to be derived from combined results of both an analysis of product specifications performed by another design section and an analysis of die specifications carried out by the die-design section. In the conventional technology, however, there is no system that can be used to make an overall decision based on fusion of results of analyses performed in a variety of design aspects by a plurality of design sections.
Points listed below are not taken into consideration by the conventional technology described above. Accordingly, the conventional technology cannot be used for performing total evaluation viewed from a plurality of different standpoints on design specifications of a product which undergoes a design process involving a plurality of design items.
(1) The conventional technology cannot be used for carrying out total evaluation based on relations among results of specific analyses for a plurality of evaluation items. Note that the analyses can be done accurately and by merely displaying their results as graphics, their relations can be observed for evaluation.
(2) When a section in charge of certain design items kicks off design activities, at an early design step, design parameters or input data are not all gathered due to a lack of uniformity in design progress among design sections which is, in some cases, caused by other design sections not starting design work yet. The uncomplete design parameters do not allow analyses to be done. Accordingly, with the conventional technique, if interdependent design activities are not carried forward until all design parameters required for analyses are gathered, neither evaluation nor analyses can be performed, resulting in a slip in the design schedule. In some cases, results of an analysis based on design parameters set under conditions desirable for preceding design items or based on design parameters set temporarily must be collated with results of another analysis based on design parameters set by a succeeding design section in order to carry out evaluation. As a result, there is normally a lack of consistency of data for ordinary evaluation.
(3) The conventional technique makes use of an analysis program which utilizes only design parameters determined by a preceding design section. In this case, an attempt is made to perform optimization based only on the design parameters which determine results. Accordingly, design margins on design parameters used in a succeeding design section hardly exist or evaluation results of succeeding design items are very likely to be inadequate or to exceed a desirable limit.
In addition, in the past, a large number of data management policies of a CAD system were announced as a method for managing design data of a product. As is disclosed in Japanese Patent Laid-open No. 2-4153, for example, design data for a product and related information required for design and manufacturing are systematically administered and three-dimensional data for FEM (Finite Element method), numerical control, analyses and other purposes is treated by relating it to its design object. In addition, in a technique disclosed in Japanese Patent laid-open No. 2-48774, information on correction such as a flag to indicate correctability and the names of correctors is added to design data for each part unit as part of the administration of the design data. In this way, design work can be carried out by a plurality of designers concurrently designing a product by sharing part data.
In the conventional techniques cited above, however, points described below are not taken into consideration. Accordingly, the techniques cannot cope easily with changes in specification resulting from study of specifications conducted by a plurality of design sections which frequently repeat the work of prototyping a product. The points not taken into consideration include the fact that in design parameters, design constraints set by estimating certain safety factors or design margins do exist. The work of setting the design constraints is based on tests and prior manufacturing experience and knowhow. Each constraint is set by a design section having the duty of determining parameter values associated with the constraint. Total evaluation from a plurality of points of view such as reliability and producibility is carried out at the prototyping stage of the product. From results of the total evaluation, an attempt may be made to change a specific design parameter. In this case, it is necessary to also modify other related design parameters which are in the domains of other design sections. If a modified design parameter exceeds its constraint value, the judgement of its merits and demerits or the possibility of eliminating its margins is left to the other section having the duty of determining the design-parameter value. When conducting a study of specifications for a plurality of design parameters, it is thus necessary for a plurality of design sections to scramble for the aforementioned margins by utilizing base data for setting the constraints.
In the conventional techniques described above, conditions of constraints mentioned above and the constraint setting base data associated with design parameters of a product are not controlled. In addition, a means for supporting the study of constraint relaxation or margin elimination is not provided either. Accordingly, the conventional techniques cannot cope with a study of specifications involving a plurality of design sections. Moreover, effects of modifying a design parameter on other design parameters in the domains of other design sections cannot be identified. As a result, the fact that a plurality of design sections or designers cannot conduct a study of specifications for a product at the same time is an undenyable reality.